Melting pot



Sept. 16, 1930. A. N. ons

' lumwrl P01l original Fileduarcn 5, 1927 Inventor: Albert N. @.t'r's, Y

His Atto-#heg Patented Sept. 16, 1930 UNITED STATES inane PATEN'I'Ty GFFCE ALBERT N. OTIS, OF SCI'IENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIG COMPANY, A CORPORATION OF NEW YORK MELTING POT .Application led. March 1927, Serial No. 173,158. Renewed February 5, 1930.

My invention relates to melting pots, more part-icularly to high temperature melting pots such as may be used for holding molten lead or cyanide for the heat treatment of steel, and

5 has for its object the provision of a simple and reliable device of this character.

For a more complete understanding of my invention reference should be had to the accompanying drawing in which Fig. 1 shows 1n an elevation view mainly in section of an electric melt-ing pot embodying my invention and Fig. 2 is a view in perspective of a metallic receptacle.

Referring to the drawing, I have shown my invent-ion in one form in connection with a pot for containing molten lead which is maintained at a comparatively high temperature, approximately 1500O F., to be used in the hardening of tools. The articles to be hard- 2o ened are immersed in the lead and when thoroughly heated are withdrawn and quenched. The device comprises inner heat refractory walls 10 forming the side and bottom walls of a cylindrical receptacle constituting a heating chamber. The walls may be built up of suitable heat refractory brick. Around the inside of the heating chamber is hung an electric heating resistor shown in upper and lower sections 11 and 12. The resistor consists of a Hat ribbon of a suitable resistance heating material, such as a nickel-chromium alloy which is hung in a series of vertical loops on metallic pins 13 secured in the side wall.

Spacing insulators 14 are provided for vthe lower ends of the loops. Suitable terminals 11a and 12a for the .resistor are brought out through the walls 10. The receptacle formed by the walls 10 rests on several layers of heat refractory bricks 15 which in turn are supported on a metallic base member 16. As

shown the bricks 15 are built out around the receptacle into engagement with an enclosing metallic casing 17 which is secured to the base 16. The space between the casing and the side wall 10 is filled with a suitable powdered heat insulating material 18, such as a diatomaceous material.

Inserted in the heating chamber is a metallic receptacle or pot 19 for the material to be melted. This receptacle is providedwith a ly to form a portion of a cone 21a, the upper opening of which is concentric with the heating chamber and surrounded wit-h a substantially vertical portion or flange 21b of such size as to iit loosely around the pot 19 which rests on its upper edge. The flange 2O on the body is provided with an outer peripheral overhanging flange 23 which fits over the upper edge of the flange 2lb. An upwardly projecting peripheral flange 24 is also provided on the flange 20, and this flange forms a seat for an annular removable member 25. The member 25 is provided with an inner flange 26 which fits inside the flange 24, while the outer edge of the member 25 rests on an annulartop plate 27 secured to the casing 17.

rllhis annular plate 27 is countersunk to receive the member 25 which is flush with the top surface thereof, and the plate 27 is also provided with an annular groove or recess 28 adjacent the outer periphery of the member 25.

lt will be observed that with this construction access is had to the receptacle through the annular member 25. rllhe heat refractory p material 18 is packed around the supporting member 21 and the upper edge of the receptacle so as to prevent loss of heat. A suitable cover 29 is provided consisting of a slab 30 of heat refractory material which is mounted in a casing 31. A layer of powdered heat refractory material 32 is provided in the casing to further increase the heat insulation. This cover is pivotally secured to a vertical pin 33 which in turn is ysecured to the plate 27 near the outer edge thereof.

A handle 34 is provided whereby the cover may be slid over the top of the receptacle and thus moved about its pivot to opened `and closed positions. A suitable thermecouple 85 may be provided to give an indication or the temperature of the material in the receptacle. An outlet opening 38 is provided in the bottom of the heating chamber to permit the escape ot the molten metal in the eyent ot leakage ot the receptacle without damage to the heating` resistor.

As previously observed this permit-s the upper end of th heaty ber and the metal receptacle to L surrounded with the heat insulating ma terim so as to conservethe heat. Another advantage ot this construction that the receptacle may be easily removed. This may be accomplished by lirs-U removing the annulaA ring 25 alter which the receptacle may be lifted out. 'l'runnions and 3"? are provided on the receptacle at o osite sides to provide for the atachment ot hoist in litting it. is the heated article are removed from the receptacle, the molt n metal drips from them on the ringan i. top plate I? from which it may be scraped back into the receptacle. Such of the drippings as may find their way into the crevice at tno junction of the ring 25 and the late 2T ai'. collected by the recess 2O. This recess 1n conjunction with the ring 25 and plate El? eti'ectually prevents the entrance of the metal drippings and other foreign materials into the'insulating material 1S. Such materials it' allowed to mix with the insulating material would decrease its heat insulating value. Besides 'liacilitating the removal otl the metal rece', tacle, the provision ot' the two parts at the top, i. e. the ring 25 and the plate 2i', brealrs up the thermal path trom the metal receptacle. rlhe joint between the two members offers a path ot high thermal resistance which greatly reduces the loss of heat by conduct' in through these parts. Y

Another feature oi" advantage lies in tlf conical porti-on 2l of the smpportiug member 2l. Vllhis inner portion or' the supporting member i-s often beate l to a much higher ten'iperature than the oute' horizon pirtion and as a result expansion i much greater than the expansion oi the outer portion. rEhis is particularly true when the pot is being initially heated. l/Vith this conical shape the upper portion lu is tree to expand and contract independently ot the outer portion so that no strains are set up. These strains if not compensated terV would cause buckling or rupture of the supporting member. This conical shape also provides for the heating et the upper end ot the metal receptacle while also providing iior a deep layer ot powdered insulating material 28 around the top of the heating chamber. The provision oit the lingers 22 around the periphery for centering the supporting member on the wall 10 also provides for freedom ot'expansion and contraction due to changes in temperature as compared, for example, with the usual continuous flange around the outer periphery. The overhanging flange 23 on the receptacle makes it impossible for any molten metal which might-be spilled to run down the outside orp the pot.

hile l have described my invention as embodied in concrete form and as operating in a specific manner in accordance with the provisions of the patent statutes, it should be yunderstood that l do not limit my invention thereto. since various modilications thereof will suggest themselves to those skilled in the without departing from the spirit ot my invention the scope of which is i'orth in the annexed claims. y

lifhat l claim as newand desire to secure by Letters Patent ot the United States, is zl. A melt'` g pot comprising a heat refractory wall forming an' open top chamber, heating means for said chamber, an annular top member for said chamber provided with an opening, said annular member being inclined toward the center, receptacle inserted .in said Y opening provided with a supporting flange resting on, said member, and an annular member resting on said liangc. i

A melting pot comprising a heat reliactory wall forming an open top chamber,- heating` means for said chamber, a supporting member on said wall provided with a central aperture and an upstanding edge surrounding iid aperture, a receptacle inserted in said aperture provided'with a supporting flange resting on and'overhanging said upstanding edge, and an annular member provided with a flange onits inner periphery fitting in Vsaid receptacle.

3. A melting pot comprising a heat retractory wall forming an open top chamber, heat- A ing means in said chamber, a top supporting member on said chamber providedwith an inclined central wall terminating in an opening, and a receptacle inserted in said opening provided with. a supporting iiange resting on said member.

ll. melting pot comprising a heat rctractory wall forming an open top chamber, heating means for said chamber, an annular. top member for said chamber having an upwardly extending conical central portion, and a receptacle inserted in said chamber provided Y flange resting on said with a support' member.

5. A melting pot comprising a heat refractory wall forming an open top chamber, heating' means tor said chamber, an annularA supporting member'on said wall having an upwardly extending conical central portion, a receptacle inserted in said member provided with a supporting flange resting on and overhanging the upper edge ot said supporting member, and heat insulating material surrounding said supporting member and the upper end of said receptacle.

6. A melting pot for heat treating metallic articles, comprising a heat refractory wall forming an open top heating chamber, heating means in said chamber, a receptacle for the molten material in said chamber, a top plate for said wall provided with a central opening through which the receptacle may be removed, an annular member iitting in said opening, and a flange on the inner periphery of said annular member fitting in the upper end of said receptacle.

7. A metal pot comprising a l,heat refractory wall forming an open top heating chamber, heating means in said chamber, a supporting member on said Wall provided with an opening concentric with vsaid chamber, a receptacle in said chamber provided with a supporting flange resting on said member, a casing around said wall in spaced relation thereto, heat refractory material between said wall and said casing surrounding the top of said receptacle, a top member onl said casing provided with an opening through which said receptacle may be removed, an annular member fitting in said opening, and a flange on the inner periphery of said annular member fitting in the upper end of said receptacle.

8. A melting pot comprising a heat refractory wall forming an open top chamber, heating means around the interior of said wall, a metallic member on said wall provided with an opening concentric with said chamber, a

receptacle in said opening provided with a supporting flange at the top resting on said member, a casing around said wall in spaced relation thereto, heat refractory material between said wall and said casing surrounding the top of said receptacle, a top member on said casing provided with a central opening through which said receptacle may be removed, an annular member fitting in said opening, and a flange -on the inner periphery of said annular member fitting in the upper end of said receptacle.

9. A melting pot comprising heat refractory walls forming an .open top chamber, heating means in said chamber, a supporting member in said wall provided with a central aperture and an upstanding edge surrounding said aperture, a receptacle inserted in said aperture provided with a supporting flange resting on and overhanging said upstanding edge, a top plate provided with an opening through which said receptacle is removable, and an annular member fitting in said opening provided with a flange on its inner periphery fitting in said receptacle, said top plate being provi-ded with a recess in its inner periphery below the outer periphery of said annular member.

10. A melting pot for heat treating metallic articles comprising a heat refractory wall forming an open top heating chamber, heating means in said chamber, an annular supporting member on said wall provided with an upwardly extending conical central portion, a receptacle set in said aperture, a casing surrounding said wall, heat refractory material between said wall and said casing surrounding the top of said receptacle, a top member provided with a central opening through which said receptacle may be removed, an annular member fitting in said opening, a flange on said annular member fitting in the upper end of said receptacle, said top member being provided with a recess around said annular member.

11. A melting pot or the like comprising a wall forming an open top chamber, heating means for said chamber, .a member having an outer portion supported by said wall and an inner portion extending at an angle with said outer portion to compensate for strains set up by unequal thermal expansion and contraction in vsaid member, said inner portion terminating in an opening, and a receptacle extending through said opening into said chamber and supported by said inclined inner portion.

12. A melting pot or the like comprising a wall forming an open top chamber, heating means for said chamber, an annular conical member at the upper end of said chamber having its outer portion supported by said wall, and a receptacle extending through said conical member into said chamber arranged to be supported by said conical member.

13. A melting pot or the like comprising a wall forming an open top heating chamber, heating means for said chamber, a member having an outer portion supported by said wall and an inner portion extending at an angle to said outer portion to compensate for strains set up by unequal expansion and contraction in said member, said inner portion terminating in an opening, a receptacle extending through said opening into said chamber, and heat insulating material around said inner portion. v

14. A melting pot or the like comprising a wall forming an open top chamber, a receptacle in said chamber, an annular member at the top of said chamber having an upwardly extending cone shaped portion surrounding said receptacle, heat insulating material around said cone shaped portion, and heating means between said receptacle and said wall.

y In witness whereof, I have hereunto set my hand this 3d day of March, 1927.

ALBERT N. OTIS. 

